Combination drill and core bit



May l0, 1955 E. B. WILLIAMS, JR 2,708,103

COMBINATION DRILL AND CORE BIT May 10, 1955 E. B. WILLIAMS, JR

COMBINATION DRILL AND CORE BIT Filed March 31 1951 4 Sheets-Sheet 3 mdf, 7 4 a 2/ a 4 7543@ mm E ,a aalafw 6 76%470 7 u 4 7% Nm 7777 wb N Mall/wf 8// //J 1M m 7,77 ,.f- 77 i A 4* 54K Y xx 8, 6 3 /d FL @M www wawww, MM40 awww W w 7 /7 /Q/ /f/,f/,//

May l0, 1955 Filed March 31 1951 E. B. WILLIAMS, JR 2,708,103

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United States Patent() COMBINATIN DRILL AND CORE BIT Edward B. Williams, Jr., Greenville, Tex.

Application March 31, 1951, Serial No. 218,644

7 Claims. (Cl. 25E-72) This invention relates to an apparatus for forming a borehole in an earth formation, and more particularly to a combination rotary drill and core bit, the principal object of the invention being to provide a drill bit with an annular drilling face encircling a removable drilling core section that has a drilling face located at a higher level than the annular drilling face to form a pilot or core progressively with formation of a borehole when the drill bit is in operation.

Further objects of the invention are to provide the bit with transverse passages extending across the annular drilling face and into the recess which receives the pilot or core for admitting a drilling iluid in cooling relation with the annulardrilling face and for conducting cuttings from the drilling face to the axial recess and from the axial recess through radial ports in the body of the bit so that the cuttings are carried to the top of the borehole circumferentially of the drill pipe; to provide for removal and replacement of the core drilling element of the bit; to provide for removal of the core drilling element by way of the drill pipe while the bit is within the borehole; I

to provide for insertion of a core barrel by way of the drill pipe to take a core; to provide for removal of the core through the drill pipe; to provide a simple and positive` latch mechanism for retaining the axial drilling core element and core barrel in position within the body of f formsof which are illustrated in the accompanying drawf ings, wherein:

Figs. l and lA are vertical sections through the upper and lower portions of a combination drill and core bit having a construction in accordance with the present invention, the drill bit being shown in connection with a string of drill pipe and in the bottom of a borehole formed thereby, the retaining latch being released and showing the latch operating device in retracted position.

Figs. 2 and 2A are similar sections but showing the core barrel in place within the drill bit and connected thereto by the latching mechanism.

Fig. 3 is a horizonal section through the body of the drill bit on the line 3-3 of Fig. 2, showing the' latch members in engaged position.

Fig. 4 is a section showing the wire line tool engaged with the overshot spear of the core drilling element by which the core drilling element is lowered through the drill pipe into position within the body of the drill bit orl is removed therefrom.

Fig. 5 is a similar section showing the wire line device released from engagement with the overshot spear.

2,708,103 Patented May 10, 1955 ice Fig. 6 is a Vertical section through a modified form of drill bit.

Fig. 7 is a cross-section through the modiiied form of drill bit on the line 7--7 of Fig. 6.

Fig. 8 is an end view of the drilling face of the bit illustrated in Fig. 6.

Referring more in detail to the drawings:

1 designates a drill bit constructed in accordance with the present invention and which includes an outer barrel 2 substantially conforming in diameter with a drill pipe 3 on which the drill bit is mounted. The barrel 2 has a threaded lower end 4 that is connected with an internally threaded box Spot a coupling 6, also preferably conforming to the outer diameter of the barrel 2. The lower end of the bit coupling is provided with a threaded pin 7 engaged in a threaded socket 8 of a bit head 9. The upper end of the barrel 2 has a threaded pin end 10 threadedly connected with the box end 11 of a lock coupling 12, which is connected at its upper end by a threaded pin 13 with the internally threaded box 14 of a safety joint 15 having threads 16 connected with internal threads 17 of a coupling 1S, the threads 16 being of opposite hand to the threads of the drill pipe so that the roation of the drill pipe may be used to effect uncoupling of the drill pipe from the drill bit should the drill bit become lodged in the borehole.

The coupling 18 is provided with a box end 19 that connects with the pin 20 of the lowermost tool joint of the drill pipe 3. The bit head 9 includes an annular drilling face 21 encircling an axial core receiving bore or recess 22 that is formed within the bit head and which connects with a counterbore 23 through a llaring portion 24. The counterbore 23 forms an annular flow passageway about a core drilling section 25 of the bit and which is carried coaxially of the outer shell from a tapered seat 26 provided on the upper end of an inner barrel 27, as later described. The drilling face 21 has water courses extending thereacross into the bore 22. The drilling face is provided between the water courses with diamonds 23.

The coupling 6 has an axial passageway 29 forming an upward continuation of the counterbore 23. A leak-tight seal is provided between the lower end of the inner barrel and the coupling 6 by means of an 0-ring 30l seated in grooves 31as shown in Fig. 1A. The upper end of the inner barrel carries a collar 32, having an axial opening 33 for passing a core tube 34, the core tube also being formed of a string of pipe suitably connected together by pin and box joints 35 and 36. The opening 33 is encircled by the seat 26 and tapers to the in ner diameter of the inner barrel. Mounted on the upper end of the tube 34 is a head 39 having a tapered shoulder engaging the seat and carrying an O-ring 41 to form a Huid-tight joint therewith, as best shown in Fig. l. The inner barrel is of smaller outer diameter than the inner diameter of the outer barrel to form an annular downow passageway 42 between the inner and outer barrels to connect with a circular series of ports 43 that are provided within the collar 6, and which connect with corresponding ports or passageways 44 in the bit head, as best shown in Fig. 1A.

The core drilling bit element 25 is supported in spaced relation with the annular drilling face 21 and has an end drilling face 45 to drill out the pilot or core 46 that is formed at the bottom of the borehole within the core lopening 22 of the bit head. The outer diameter of the core tube is of smaller diameter than the inner diameter of the inner barrel to provide an annular passageway 47 therebetween and the core tube is retained in concentric relation with the inner barrel by guides 48, as best shown in Fig. 1A. The inner barrel is similarly retained in coaxial alignment with the outer barrel by vertical ribs 49. The core tube thus forms a passageway 50 for supplying drilling fluid to the drilling face of the core drilling section through a port 51 that extends through the body of the core drilling section and which discharges adjacent the periphery of the drilling face thereof. The drilling fluid passes outwardly under the drilling face and into the outlet passage 23 where it joins with the ilow of drilling uid from the annular drilling face and passes through lateral ports 52 that are provided within the wall of the collar 6, as shown in Fig. 1A.

The bit section 25 is removably connected with the core tube by a threaded connection 53. A leak-tight seal is provided between the inner barrel 27 and the coupling by an O-ring 54 as shown in Figs. 1A and 2A. In order that the core tube and core drilling element 25 carried thereby may be lowered through the drill pipe into the drill bit and removed therefrom through the drill pipe, the head 39 has an internally threaded socket 55 for engaging the threaded end 56 of a latch and spear housing 57 which extends through a guide opening 58 within an internal collar 59 that is formed on the inner side of the coupling 12 and which has a tapering upper face 60 to guide the core drilling element of the bit through the opening 58 for seating the head 39 on the seat 26.

The latch spear housing has an outer diameter to pass freely through the opening 58 and an inner diameter to accommodate inward swinging movement of latch dogs or detents 61, the detents 61 being pivotally mounted within slots 62 that are formed in the wall of the housing, as shown in Fig. 1. The detents are supported on pins 63 that extend transversely of the slots. The detents depend within the slots and have wedge-shaped portions or lugs 64 that extend laterally therefrom and which are adapted to engage in wedge-shaped grooves 65 that are provided within the internal flange 59, so that the core tube is anchored in position within the drill bit. The detents are normally retained in retracted position by leaf springs 66 that are carried by the lower ends of the detents and engage the opposite diametric sides of the latch and spear housing 56. The springs retain the detents with the lower ends thereof in abutting relation so that when the core tube and core drilling bit element carried thereby is lowered through the drill pipe the wedge-shaped lugs 64 are retained within the contines of the housing 56. The detents are adapted to be moved into engagement with the wedge-shaped recesses 65 by means of a spear 67 that is slidably mounted within an axial opening 68 in an upward part of the latch spear housing, the spear being provided with a collar 69 that is reciprocably mounted within a bore 70 of the housing extension.

The spear extends upwardly through the opening 68 and carries a head 71. The head 71 includes an upward stem 72 having a collar 73 that is provided with a bevelled upper face 74 encircling an upward continuation l75 of the stem and which terminates in a cone-shaped terminal 76 forming an annular shoulder 77 that is Y adapted to be gripped by a running-in tool 78, later described.

The spear 67 is retained in retracted position by a ball latch 79 that is mounted in a transverse bore 80 in the collar 69, previously described, the ball being urged into engagement with a recess 81 of the spear housing by means of a coil spring 82 having one end seated in the bottom of the transverse bore and to the end bearing against the ball 79.

The tool 78 includes a sleeve-like body 83 having a swedged lower end 84 encircling an opening 85 of sufficient diameter to pass over the terminal 76 but which is adapted to engage the collar 73. The upper end of the sleeve 83 carries a head 86 provided with an axial bore 87. Slidably mounted in the bore 87 is a rod 88 carrying a cylindrical plunger 89 on the lower end thereof and which is adapted to spread a plurality of gripping fingers 90 that are carried from a sleeve 91 threaded on a reduced neck 92 of the head 86. The fingers 90 are adapted to encircle the cone terminal 76 and have hookshaped ends 93 that are adapted to engage under the shoulder 77 thereof as best shown in Fig. 4. The ngers have cam portions 94 that extend inwardly thereof and which have upper and lower tapering portions 95 and 96 adapted to be engaged by a bevelled end 97 of the plunger 89 and the cone-shaped terminal 76 respectively.

Carried by the upper end of the head 82 is a rope socket 98 having an axial bore 99 receiving the upper end of the rod 88. The rod 88 carries a pin 100 that extends transversely through the terminal end thereof and has laterally projecting ends 101 guidingly mounted in slots 102 that are provided in opposite sides of the rope socket. Carried on the upper end of the rod 88 is a detent in the form of a spring leaf 103 that extends through a constriction 104 in the bore 99 to form a shoulder 105 to be engaged by a hook 106 on the end of the detent 103 for holding the plunger in retracted position, as shown in Fig, 4. Connected with the socket 98 is a cable 107 by which the mechanism is lowered into or removed from the drill pipe. The detent 103 is adapted to be released from the shoulder by means of a sleeve-like jar that is dropped over the wire-line 107 to drive against the projecting ends 101 of the transverse pin 100 as shown in Fig. 5.

In Figs. 2 and 2A the core tube is removed and substituted by a core barrel 110 that is adapted to be lowered through the drill pipe and supported in position within the drill bit to receive the core 111 as shown in Fig. 2A. The barrel 110 conforms to the outer diameter of the core tube previously described, but has a substantially thinner wall to permit free entrance of the core therein. The lower end of the tube is provided with a core catcher 112 which is of conventional type so as to support the core within the barrel when the barrel is to be withdrawn as later described. The barrel 110 is carried from a head 113 corresponding with the head 39 previously described. The head 113 is connected with the latch spear housing previously described and carries a swivel 114. The swivel includes a member 115 that is threaded in the upper end of the core barrel, as indicated at 116, and has inwardly stepped shoulders 117 and 118 to form annular shoulders corresponding with similar shoulders 119 and 120 within a swivel member 121 that is threadedly connected with the head 113, as indicated at 122. Supported between the respective shoulders 118 and 120 is an antifriction bearing 123. The member 115 has an extension 124 that extends upwardly through the member 121 and is journalled within a thrust bearing 125 that is carried within a cylindrical bore 126 that is formed within the head 113, a collar 127 being threaded on the upper end of the extension 124 to engage the thrust bearing and support the core barrel in proper position with respect to the drill bit. Suitable rubber washers 128 may be inserted between the bearings to maintain the desired fit.

The members 115 and 121 of the swivel are provided with oil seals 129 that are retained between the shoulders 117 and 119 to retain a lubricant indicated at 130. The lubricant 130 is admitted through a pressure fitting 131 into an axial bore 132 of the member 115 which connects at its lower end with a pressure cylinder 133 in which is mounted a piston 134 to apply pressure on the body of lubricant responsive to pressure of the drilling uid, the drilling fluid acting through a lateral port 135 against the bottom side of the piston. The lower end of the cylinder is closed by a suitable plug 136 after the piston has been inserted. The lubricant channel extends upwardly and discharges into the recess 126 from where the lubricant iiows downwardly to lubricate the respective bearings.

The form of the invention shown in Fig. 6 includes a drill bit 140 that has a diamond head 141 similar to the head 9 previously described, which has a circular series of vertical ports 142 that connect with a chamber 143 in the bit coupling 144, the chamber 143 being con-i nected with the passageway 145 through the drill pipe 146. The bit head has an annular drilling face 147 encircling a bore or recess 143 to receive a core or pilot 149 when the bit is in use. ln this form of the invention the core or pilot is drilled away by a core bit element 150 that is threaded within a socket 151 of the bit coupling 144. The bit element 150 has a drilling face 152 substantially conforming to the drilling face of the core drilling element previously described and is provided with a water course 153 that connects with the chamber 143 through a port 154. The shank 155 of the core drilling element of the bit is encircled by a passageway 156 from which the drilling fluid and cuttings are discharged through upwardly and outwardly directed ports 157 similar to the corresponding ports of the bit previously described. The drilling face 147 may be provided with radial water courses 158 that connect with the outlet of the ports 142 through connecting channels 159 which also connect with the recess 148, as best shown in Fig. 8. The core drilling element, as well as the face portion of the annular drilling face are provided with diamonds or other abrading elements 160. The abrading elements may extend upwardly around the marginal portion of the bit head to provide the desired clearance for a portion of the drilling uid to wash upwardly together around the head of the bit while the major portion tlows inwardly and then outwardly through the ports 157. In this form of the bit the entire drilling string must be removed to effect removal and replacement of the core drilling section of the bit.

In using the apparatus for drilling a borehole, it is assembled as described and connected with the lower joint of drill pipe as shown in Figs. l-lA. However, the spear 67 is engaged between the latches 61 so that the lugs 64 are held in engagement With the recesses 65 to provide a driving connection between the drill pipe and the inner core tube which carries the core drilling element 25. As the drill is rotated, a hydraulic nid is pumped under pressure, as in conventional practice, through the drill pipe, through the ports 109 and down the outer passageways 42 and 43 for discharge through the ports 44 of the drill bit. As the drill is rotated the abrassive elements 28 cut the surface of the formation and the drilling uid, being discharged through the transverse passageways, carries the cuttings across the face of the bit to the core recess 22, A part of the drilling lluid, however, flows outwardly across the drilling face and up the space between the wall and the borehole and the outer core barrel. The drilling lluid passing into the recess 22 flows upwardly in the passageway 29 and is discharged through the radial ports 52,

where it unites with the upflow of drilling iluid and is discharged from the top of the borehole, carrying the cuttings therewith. The fluid thus flows transversely across the annular drilling surface of the bit to keep the bit and particularly the central portion thereof in cool condition and to remove the cuttings made by the abrasive elements. Simultaneously drilling uid is discharged under pressure through the bore 50 of the core tube to pass through the port 51 and cool the face 45 of the core drilling element 25, which drills up the core 46 progressively with deepening of the borehole by the annular drilling face 21 of the bit.

When it is desired to take a core, the core drilling element 25 and its supporting tube are removed through the interior of the drill pipe. This is effected by lowering the tool 78 on the cable or wire line 107, as shown in Fig. 4, downwardly through the drill pipe so that lthe sleeve or housing 83 thereof passes over the cone end 76 of the stem 72 to cause the latches 93 to engage the shoulder 77 of the cone. The core tube is then connected with the cable 107 and by withdrawing the cable the spear is disengaged from the latches so that their springs may retract them to release the core tube. The spear is then retained in retractive position by engagement of the ball latch 79. At the same time the collar engages the internal shoulder below the opening 68 and further withdrawal lifts the core drilling tube with the core drilling element from the borehole.

The spear and latch housing carrying the spear and latch assembly is then disengaged from the head of the core tube and screwed onto the head of the core barrel by effecting engagement of the threads 55. The spear is latched in retracted position so that the collar 69 enjgages the internal shoulder surrounding the opening 68. The unit is then lowered through the drill pipe until the core barrel head 113 engages the seat 26 on the upper end of the inner barrel 27. The core barrel is then suspended within the inner barrel and in position to receive the core 46 therein. The lowering-in tool is then disconnected from the spear and latch housing by dropping the sleeve 108 downwardly over the lowering-in cable or wire 107 to cause the sleeve to engage the projecting ends of the pin 101 and move the plunger 89 downwardly so that the coned end 97 thereof engages the cams 94 for spreading the latches 93 and freeing them from engagement with the shoulder 77. The cable including the lowering-in tool is then free to be removed through the core barrel. The spear then drops under its own weight to cause the latches 61 to reengage their clutch engagement with the clutch coupling 12'to anchor the core barrel. The drilling operation may then proceed with the core passing into the core barrel.

When it is desired to remove the core, the lowering-in tool is again passed through the drill pipe until the latches 93 of the lowering-in tool reengage the shoulder 77. After engagement the cable is withdrawn from the well. The initial movement raises the spear so that the springs 66 are effective in retracting the lugs 64 to release the latch connection, whereupon the entire core barrel containing the core is removed through the drill pipe. If further core is to be taken, the core barrel may be returned as previously described. However, if the drilling is to be continued without taking a core, the core tube and core drilling element are attached to the lowering-in tool and inserted through the drill pipe, as previously described.

When the core barrel is in use the pressure of the drilling uid in the upow passageway 29 acts through the port against the lower end of the piston 134 to apply pressure on the body of lubricant and prevent inilltration of drilling lluid into the lubricant chamber.

From the foregoing it is obvious that I have provided a combination rotary drill and core bit wherein the bit is provided with ample drilling iluid to wash the cuttings from the face of the drill bit to keep the drill bit and particularly the central portion thereof in cool oondition. lt is also obvious that the direction of flow of drilling tluid assures positive removal of the cuttings from the central portion of the bit and about the drilling face of the core drilling element.

The drilling operation of the form of the invention shown in Fig. 6 conforms with the structure illustrated in Fig. l-A, however, when the core drilling element is to be removed it is necessary to withdraw the entire drilling string. It is obvious that the passage of drilling iiuid is the same as in the rst described form of drill bit.

What I claim and desire to secure by Letters Patent is:

1. In an apparatus for forming a borehole in an earth formation, a rotary member having an end provided with an annular drilling face encircling an axial core receiving recess and having longitudinal drilling iluid supply ports opening through the annular drilling face intermediate the.

inner and outer circumferences of said drilling face, said drilling face having passages extending thereacross from said ports inwardly to the core receiving recess and from said ports outwardly to the circumference of the rotary member for discharging the drilling fluid in cooling relation with the drilling face and for conducting cuttings under the drilling face to said recess and borehole respectively, and said rotary member having an upward continuation of the core receiving recess to provide a passage for drilling fluid and having an outlet connected with the recess and opening through the circumference of the rotary member for creating ow of the drilling fluid and cuttings inwardly across the drilling face into the core receiving recess and through the outlet for upward ow through the borehole along with the drilling uid and cuttings discharged circumferentially of the drilling face, and a core drill in said rotary member and having a drilling face to drill out the core, said core drill having a drilling fluid supply port opening through the drilling face thereof for discharging drilling fluid for washing core cuttings outwardly across said drilling face and directly into the core receiving recess.

2. In an apparatus for forming a borehole in an earth formation, a rotary member having an end provided with an annular drilling face encircling an axial core receiving recess and having longitudinal drilling fluid supply ports opening through the annular drilling face intermediate the inner and outer circumferences of said drilling face, said drilling face having passages extending thereacross from said ports inwardly to the core receiving recess and from said ports outwardly to the circumference of the rotary member for discharging the drilling fluid in cooling relation with the drilling face and for conducting cutinto the core receiving recess for discharge through said u outlet for upward flow through the borehole along with the drilling uid and cuttings discharged outwardly and circumferentially of the drilling face, and a core drill in said upward continuation of the core receiving recess and having a drilling face inset upwardly from the annular drilling face for drilling out the core progressively with its formation, said core drill having a drilling fluid supply port opening through said drilling face of the port of said core drill for discharging drilling fluid to wash the core cuttings from said drilling face into said passage and for discharge through said outlet.

3. In an apparatus for forming a borehole in an earth formation, a substantially cylindrical rotary member having an end provided with an annular drilling face encircling an axial core receiving bore and having drilling uid supply ports extending longitudinally through said member and discharging through the annular drilling face intermediate inner and outer circumferences thereof. said drilling face having passages extending thereacross from said ports inwardly to said bore and from said ports outwardly to the circumference of the rotary member for discharging the drilling Huid in cooling relation with the drilling face and for conducting cuttings from the drilling face to said axial bore and borehole respectively, a core member within the axial bore and of smaller diameter than the axial bore to provide an annular upward passage therearound for conducting the drilling fluid and cuttings discharged into said bore, said rotary member having an outlet opening extending from the annular upow passage and discharging through the circumference of the rotary member, and means in the rotary member for removably retaining the core member within said bore.

4. In an apparatus for forming a borehole in an earth formation, a substantially cylindrical rotary member having an end provided with an annular drilling face encircling an axial core receiving bore and having drilling fiuid supply ports extending longitudinally of the rotary member and discharging through the annular drilling face intermediate inner and outer circumferences of said drill- 4 ing face, said drilling face having passages extending thereacross from said ports inwardly to said bore and from said ports outwardly to the circumference of the rotary member for discharging the drilling fluid in cooling relation with the drilling face and for conducting cuttings from the drilling face to said axial bore and borehole respectively, a core member within the axial bore and of smaller diameter than the axial bore to provide an annular upow passage therearound for conducting the drilling fluid and cuttings discharged into said bore through said inward passages, said rotary member having an outlet opening in connection with the annular upflow passage and discharging through the circumference of said rotary member for conducting inward flow of drilling fluid and cuttings from said inward passages for upflow exteriorly of the rotary member, and means in the rotary member for removably retaining the core member within said bore with one end spaced inwardly from the annular drilling face to form a core receiving recess, said end being provided with a drilling face for drilling off the core progressively with the drilling effected by the annular drilling face when the apparatus is in use within a borehole.

5. In an apparatus for forming a borehole in an earth formation, a substantially cylindrical rotary member having an end provided with a circular drilling face encircling an axial core receiving bore and having drilling fluid supply ports extending longitiudinally of said rotary member and discharging through the circular drilling face intermediate inner and outer circumferences thereof, said drilling face having passages extending thereacross from said ports inwardly to said bore and from said ports outwardly to the circumference of the rotary member for discharging the drilling fluid both inwardly and outwardly from said ports in cooling relation with the drilling face and for conducting cuttings from said inward passages to said axial bore and through the outer passages to the borehole, a core member within the axial bore and of smaller diameter than the axial bore to provide an annular upflow passage therearound for conducting the drilling fluid and cuttings upwardly of said bore, said rotary member having an outlet opening extending from the upper end of the annular upow passage and discharging through the circumference of the rotary member, said rotary member having a seat therein, means on the core member engaging said seat, and a latch carried by one of the members and engaging the other for removably retaining the core member on said seat within said bore with one end spaced inwardly from the annular drilling face to form a core receiving recess, said end being provided with a drilling face for driling off the core progressively with the drilling effected by the annular drilling face when the apparatus is in use within a borehole. A

6. In an apparatus for forming a borehole in an earth formation, a substantially cylindrical rotary member including an outer barrel, a bit carried by the outer barrel and having a circular drilling face encircling an axial core receiving bore in said bit and having drilling fluid supply ports extending longitudinally of the bit and discharging through the circular drilling face intermediate inner and outer circumferences thereof, said drilling face having passages extending thereacross from said ports inwardly to said bore and from said ports outwardly to the circumference of the rotary member for discharging the drilling uid in cooling relation with the drilling face and for conducting cuttings from the drilling face to said axial bore and borehole respectively, an inner barrel in the outer barrel and forming therewith a downow passage connected with said longitudinal ports, a core member within the inner barrel and extending into said axial bore and of smaller diameter than the axial bore to provide an annular upow passage therearound for conducting the drilling uid and cuttings discharged into said bore, said rotary member having an outlet opening extending from the annular upow passage and discharging through the circumference of said rotary member, and means in the rotary member for removably retaining the core member within said bore with one end spaced inwardly from the annular drilling face to form a core receiving recess, said end being provided with a drilling face for drilling oil the core progressively with the drilling effected by the annular drilling tace when the apparatus is in use within a borehole.

7. In an apparatus for forming a borehole in an earth formation, a substantially cylindrical rotary member including an outer barrel, a bit carried by the outer barrel and having a circular drilling face encircling an axial core receiving bore in said bit and having drilling uid supply ports extending longitudinally through the circular drilling face intermediate outer and inner circumferences thereof, said drilling face having passages extending thereacross from said ports inwardly to said bore and from said ports outwardly to the circumference of the rotary member for discharging the drilling fluid in cooling relation with the drilling face and for conducting cuttings from the drilling face to said axial bore and borehole respectively, an inner barrel in' the outer barrel and forming therewith a downflow passageway and connected with said longitudinal ports for the supply of drilling Huid, a core member within the inner barrel and extending into said axial bore and of smaller diameter than the axial core to provide an annular upow passageway therearound for conducting the drilling iluid and cuttings discharged into said bore, said rotary member having an outlet opening extending from the annular upow passage and discharging through the circumference of said rotary member, said inner barrel having a head provided with a seat for the core member, and latch means in the core member engageable with a part of the rotary member to retain the core member in engagement with said seat to support the core member and to separate the up and downow passageways.

References Cited in the le of this patent UNITED STATES PATENTS 1,867,024 Oliver July l2, 1932 2,189,057 Copelin Feb. 6, 1940 2,421,997 Crake June 10, 1947 2,495,400 Williams Jan. 24, 1950 2,555,580 Deely June 5, 1951 2,660,402 Devine et a1. Nov. 24, 1953 

